Reactions of formate and ethanol radicals with bovine serum albumin studied by electrophoresis.

Radiation-induced reactions of formate and ethanol radicals with bovine serum albumin were studied by electrophoresis. The reaction products were separated as reduced and unreduced SDS-protein-complexes on polyacrylamide gel. Quantitative evaluation of the densitometric measurements gives information about the reaction mechanisms. Initially formate radicals react rapidly and very selectively with the disulphide groups which then form partly intermolecular S-S-bonds. This formation of reducible aggregates causes a massive loss of serum albumin. With increasing dose unreducible aggregates are formed. Formate radicals show a high efficiency in both degradation processes, which are not caused by ethanol radicals. Formate radicals are much more effective in degrading serum albumin than ethanol radicals. Both radicals show a third degradation process which has low G-values and is presumably caused by H-abstraction.